In modern society, elevators have become ubiquitous machines for transporting people and cargo through buildings of multiple stories. As elevators are operated continually throughout the day making frequent stops at various floor levels, the safety monitoring system of an elevator plays an important role in ensuring reliable operation of the elevator.
Elevator safety codes require, among other things, that the speed of the elevator be checked as it approaches a terminal landing to ensure that the speed can be reduced to a reasonable safe speed as it approaches the landing. One current method widely adopted is the use of switches and cams to determine if the elevator is slowing down. However, the installation of the switches and cams is quite costly, not to mention the significant maintenance these switches and cams require.
Another method currently used to determine speed of the elevator is by utilizing an elevator positioning system. Many current elevator positioning systems use elevator car position information, which is derived from encoders and/or switches, to determine not only the position of the elevator car, but also the speed of the elevator car. The installation of such positioning systems is also quite costly.
In light of the foregoing, improvements continue to be sought for a cost effective system to determine the speed and position of an elevator car.